1,734 research outputs found
Measurement of neutron spectra in liquid hydrogen Quarterly progress report, period ending Dec. 17, 1965
Neutron spectra measurement in liquid hydrogen, water cooled fast neutron source, thermal neutron measurements, and liquid hydrogen facility checkout using nitroge
Measurement of neutron spectra in liquid hydrogen final report
Neutron spectrum measurement in liquid hydrogen and wate
Gamma and neutron dose measurements for a thermal tungsten nuclear rocket critical experiment
Measurements of gamma and neutron dose distributions in core of thermal tungsten nuclear rocket experimen
Measurement of neutron spectra in liquid hydrogen Quarterly progress report, period ending Mar. 17, 1966
Measurement of neutron spectra in liquid hydroge
Reevaluation and analysis of neutron spectra in liquid hydrogen Final report
Neutron spectra for various thicknesses of liquid hydroge
Possible Observational Criteria for Distinguishing Brown Dwarfs from Planets
The difference in formation process between binary stars and planetary
systems is reflected in their composition as well as their orbital
architecture, particularly orbital eccentricity as a function of orbital
period. It is suggested here that this difference can be used as an
observational criterion to distinguish between brown dwarfs and planets.
Application of the orbital criterion suggests that with three possible
exceptions, all of the recently-discovered substellar companions discovered to
date may be brown dwarfs and not planets. These criterion may be used as a
guide for interpretation of the nature of sub-stellar mass companions to stars
in the future.Comment: LaTeX, 11 pages including 2 figures, accepted for publication in the
Astrophysical Journal Letter
Measurement of neutron spectra in liquid hydrogen Final report
Differential energy flux neutron spectra in liquid hydrogen obtained by time-of-flight technique
Tungsten nuclear rocket, phase I, part 1 Final report
Tungsten water moderated nuclear rocket reactor experiments and analyse
Resource Prospector: Evaluating the ISRU Potential of the Lunar Poles
Resource Prospector (RP) is a lunar volatiles prospecting mission being developed for potential flight in CY2021-2022. The mission includes a rover-borne payload that (1) can locate surface and near-subsurface volatiles, (2) excavate and analyze samples of the volatile-bearing regolith, and (3) demonstrate the form, extractability and usefulness of the materials. The primary mission goal for RP is to evaluate the In-Situ Resource Utilization (ISRU) potential of the lunar poles
How Dry is the Brown Dwarf Desert?: Quantifying the Relative Number of Planets, Brown Dwarfs and Stellar Companions around Nearby Sun-like Stars
Sun-like stars have stellar, brown dwarf and planetary companions. To help
constrain their formation and migration scenarios, we analyse the close
companions (orbital period < 5 years) of nearby Sun-like stars. By using the
same sample to extract the relative numbers of stellar, brown dwarf and
planetary companions, we verify the existence of a very dry brown dwarf desert
and describe it quantitatively. With decreasing mass, the companion mass
function drops by almost two orders of magnitude from 1 M_Sun stellar
companions to the brown dwarf desert and then rises by more than an order of
magnitude from brown dwarfs to Jupiter-mass planets. The slopes of the
planetary and stellar companion mass functions are of opposite sign and are
incompatible at the 3 sigma level, thus yielding a brown dwarf desert. The
minimum number of companions per unit interval in log mass (the driest part of
the desert) is at M = 31^{+25}_{-18} M_Jup. Approximately 16% of Sun-like stars
have close (P < 5 years) companions more massive than Jupiter: 11% +- 3% are
stellar, <1% are brown dwarf and 5% +- 2% are giant planets. The steep decline
in the number of companions in the brown dwarf regime, compared to the initial
mass function of individual stars and free-floating brown dwarfs, suggests
either a different spectrum of gravitational fragmentation in the formation
environment or post-formation migratory processes disinclined to leave brown
dwarfs in close orbits.Comment: Conforms to version accepted by ApJ. 13 pages formatted with
emulateapj.cl
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